A method and apparatus for estimating the remaining capacity of a lithium-iodine battery through the nomographic analysis of two or more measurements of battery impedance. In a preferred embodiment, a pacemaker or other implantable medical device is provided with circuitry for periodically measuring...http://www.google.ca/patents/US5391193?utm_source=gb-gplus-sharePatent US5391193 - Method and apparatus for battery depletion monitoring
